Instability free routing: beyond one protocol instance

View/Open

Download Record

Author

Date

Metadata

Abstract

Today, a large body of research exists regarding the correctness of routing protocols. However, many reported global diisruptions of Internet connectivity, e.g., inter-AD persistent loops, cannot be explained by looking at a eingle routing protocol at a time. In fact, these anomalies have long been suspected in the operator community to be caused by the interactions between routing protocols. The interactions between protocol instances are governed by two proceduress at the boeder routers: route selection (RS) ranks routes from different protocol instances; and route redistribution (RR) exchanges routes between protocol instances. Prior studies hypothesized that RR may be responsible for a portion of the observed anomalies. In this paper, we provide analytical and experimental results to link RS, RR, and their interplay to anomalies discovered in operational networks. We show that RS by itself can cause route oscillations and loops, and that in all Cisco, Quagga, and XORP implementations, non-deterministic behaviors may occur because of their incorrect modeling of the dependencies between RS and RR. We identify the root cause for each of the instabilities and derive a configuration guideline as well as a functional model to elinimate them.

Related items

In recent years the emergence of optical fiber and its correspondingly high data rates have led to the development of much higher speed networks, both locally and over the long haul. These developments led to the design ...

The current Distributed Interactive Simulations (DIS) Protocol has a limited ability to support real time, simulated engagements of more than 1000 entities because of its excessive use of network resources. It also lacks ...

A group membership protocol ensures agreement and consistent commit actions
among group members to maintain a sequence of identical group views in spite of
continuous changes, either voluntary or otherwise, in processors' ...